Fluidized bed reactor and process

ABSTRACT

The present invention is directed to a continuous process for producing a desired hydrocarbon product using a heterogeneous slurry catalyst, to the product of said process, and to the reactor utilized in such process.

[0001] This application claims priority to U.S. Provisional PatentApplication No. 60/024,891, filed Aug. 30, 1996.

FIELD OF THE INVENTION

[0002] The present invention relates to a method for carrying out achemical reaction with at least one reactant in the liquid phase using asolid catalyst. In particular, the present invention relates to acontinuous method for processing liquid hydrocarbon reactants using aheterogeneous catalyst. Specifically, the present invention relates to acontinuous method for processing liquid hydrocarbon reactants using asolid catalyst in powder form to achieve high conversions.

BACKGROUND OF THE INVENTION

[0003] Catalytic reactions involving at least one or more liquidreactants with a solid catalyst are common. Typically, such reactionsare carried out in one of several different types of reactors.

[0004] As taught in Kirk-Othmer, Volume 19, 1983 edition, pages 880-891,which is incorporated by reference herein, many reactors,configurations, and designs have evolved over the years. The specificreactor selection is based on the physical properties of each of thefeeds to the reactor and to each of the products from the reactor, i.e.vapor, liquid, solid, or combinations; the characteristics of thechemical reactions to be carried out in the reactor, i.e. reactantconcentrations, reaction rates, operating conditions, and heat additionor removal; the nature of any catalyst used, i.e. activity, life, andphysical form; and the requirements for contacting reactants andremoving products, i.e. flow characteristics, transport phenomena, andmixing and separating mechanisms. These factors are interdependent andmust be considered together. The requirements for contacting reactantsand removing products are the paramount focus of reactor technology,with the other factors usually being set by the selection of thereacting system and intended levels of reactant conversion and productselectivity.

[0005] Processes considered “high conversion” are those in which thechemical reaction approaches the point of equilibrium. One example ofsuch a process is the isomerization of 5-vinyl-2-norbornene (“VNB”) to5-ethylidene-2-norbornene (“ENB”). ENB is used as a termonomer in theproduction of films for food wrap. When producing ENB, greater than99.7% conversion is required in order to meet governmental healthregulations.

[0006] Typical liquid phase reactions with solid catalysts that requirehigh conversions (conversions approaching equilibrium) include a batchreaction with slurry catalyst, a continuous reaction in a fixed staticbed reactor, or a series of continuous stirred or mixed reactors withslurry catalysts.

[0007] Fluid bed reactors, in which at least one of the reactions occursin the gas phase, or in the liquid phase with a gas phase also present,offer the following advantages of (1) small catalyst particles can beutilized, which offer excellent mass transfer to the catalytic surface,but which are too small to practically use in a fixed bed due to highpressure drops; (2) high coefficients of heat transfer, which allow forthe continuous addition or removal of heat for excellent temperaturecontrol of the reaction; and (3) catalysts can be easily added andwithdrawn, either continuously or periodically, which is useful when acatalyst is used that loses activity over time and must be purged.

[0008] For example, U.S. Pat. No. 3,901,660 teaches a method to providemixing of a heterogeneous catalyst in a fluidized bed reactor byintroducing bubbles to mix the reactant together. The gas may be inertand be used simply to agitate the bed or may be non-inert and act alsoas a reactant.

[0009] However, such fluidized beds, which have a gas phase present, arenot useful for high conversion reactions in which a close approach toequilibrium is desired, because the agitation achieved by the gasbubbles results in back-mixing of the liquid; thus, creating a mixedflow regime. Thus, the close approach to equilibrium is prevented.

[0010] Other examples of liquid phase reactions using a solid catalystemploy either mixed slurry reactors, fixed beds, or fluid beds with agas phase also present. In all of these examples, high conversions areachieved by placing multiple mixed reactors in series, or by batchreactions, or by use of fixed bed reactors, or by use of co-currentliquid/catalyst flow reactors.

[0011] There are several ways to achieve high conversion reactions,including batch reactor, a plug flow reactor, or several continuousstirred tanks. In industry, it is most pragmatic to do severalcontinuous stirred tanks and try to put as many continuous stir tanks toachieve plug flow as if one was using a fixed bed. When one uses a fixedbed though, one needs a solid catalyst. However, if one has a catalystrequirement that it be in a powder form, a fluidized bed is required,which therefore results in a loss of conversion rates.

[0012] It would be desirable if a process method could be developed toenable one to carry out a chemical reaction between liquid reactantsusing a powdered catalyst in a continuous mode of operation, withouthaving to sacrifice conversion rates, rather than having to operate in abatch system.

SUMMARY OF THE INVENTION

[0013] The present invention relates to a continuous process forproducing a desired hydrocarbon product from a conversion chemicalreaction which utilizes a solid catalyst in powdered form comprising:

[0014] a) providing a reactor having a top portion and a bottom portionwherein the length to diameter ratio of the reactor is greater thanabout 2:1;

[0015] b) loading a powdered heterogeneous catalyst into said reactor;

[0016] c) feeding to said bottom portion of said reactor at least oneliquid reactant at a velocity sufficient to disperse said catalyst insaid liquid reactant without the use of agitation or back mixing to forma bed reaction zone wherein said velocity is at least equal to theminimum fluidization velocity and less than the minimum entrainmentvelocity wherein catalyst exits said bed reaction zone in the liquid;

[0017] e) subjecting said liquid reactant to catalyzing conditions insaid bed reaction zone whereby said desired hydrocarbon product isformed; and

[0018] f) removing said desired hydrocarbon product from said topportion of said reactor.

[0019] Another embodiment relates to a hydrocarbon product produced by aprocess using a heterogeneous slurry catalyst comprising

[0020] a) providing a reactor having a top portion and a bottom portion;

[0021] b) feeding to said reactor a slurry comprising a powderedheterogeneous catalyst;

[0022] c) subsequently feeding to said bottom portion of said reactor atleast one liquid reactant at a velocity sufficient to disperse saidcatalyst in said liquid reactant to form a dense slurry bed reactionzone having a top portion and a bottom portion;

[0023] d) subjecting said liquid reactant to appropriate catalyzingconditions whereby said desired product is formed; and

[0024] e) removing said desired product from said top portion of saidreactor.

[0025] An additional embodiment includes a reactor for producing adesired hydrocarbon product using a heterogeneous slurry catalystcomprising

[0026] a) a top portion and a bottom portion;

[0027] b) means for feeding a slurry to said reactor comprising apowdered heterogeneous catalyst;

[0028] c) means for subsequently feeding to said bottom portion of saidreactor at least one liquid reactant at a velocity sufficient todisperse said catalyst in said reactor to form a dense slurry bedreaction zone having a top portion and a bottom portion;

[0029] d) means for subjecting said liquid reactant to appropriatecatalyzing conditions whereby said desired product is formed; and

[0030] e) means for removing said desired product from said top portionof said reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 is a schematic representation of a reactor suitable for usein the present invention.

[0032]FIG. 2 is a graph of the bed expansion ratio as a function of thesuperficial fluid velocity from Comparative Example A.

DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention relates to a method for carrying out areaction in the liquid phase using a solid catalyst in powder form toachieve high conversions. In particular, it relates to any application,which has the following characteristics:

[0034] Continuous process;

[0035] Conversion of reactant(s) approaching that of equilibrium;

[0036] Absence of a gas phase (bubbles);

[0037] Catalyst is difficult to form into particles of sufficient sizeto use in a fixed bed; and/or

[0038] Continuous or semi-continuous feed and withdrawal of catalyst isdesired.

[0039] In the present invention, a heterogeneous slurry catalyst ismixed with at least one or more liquid hydrocarbon reactants to form acatalyst/reactant mixture. The mixture acts substantially like a fluidwhich moves up the reactor and allows for ease in recovering both thedesired product and the spent catalyst during substantially continuousoperation. In essence, the present invention achieves the advantages ofusing multiple stirred-tanks in series without the need to use multipletanks.

[0040] The present invention provides the method of having the effect ofplug flow without the requirement that both reactants be in a liquidphase.

[0041] The present invention is useful in connection with any reactionin which a catalyst may be used in a liquid fluidized bed where highconversion is desired. Preferable reactions for use with the presentinvention include reactions designed to alkylate, hydrogenate,isomerize, and polymerize various compounds.

[0042] The invention is suitable for a reaction with one or morereactants. At least one of the reactants must be in the liquid phase andhave no separate gas phase It is acceptable if one reactant is a gas, aslong as no separate gas bubbles can be detected. With a gas reactant, itis still possible to practice the invention if (a) the gas is dissolvedinto the liquid reactant phase first or (b) the gas is adsorbed onto thecatalyst prior to the catalyst being introduced in the reactor.

[0043] The product cannot be gaseous but must be in the liquid phase.Trace impurities may be present in the reactant feed and form gaseousbyproducts. The level of trace impurities must be low enough such thatonly negligible amounts of bubbles are produced by the reaction.

[0044] Any heterogeneous catalyst should be suitable for use in theinvention as long as it has (1) a particle density higher than theliquid reactants, and (2) a particle size small enough to fluidize uponaddition of the liquid reactants. The mean particle size may be lessthan 1000 microns, preferably less than 500 microns, and most preferablyless than 100 microns. Preferred catalysts for use in the presentinvention are powdered catalysts in which the maximum particle sizeratio (largest to smallest) of at least 95% of the particles is lessthan about 10:1. Examples of such catalysts include alumina, nickel,silica, zeolite, and clay-based catalysts. The height to diameter ratioof the fluid bed must be at least 2:1 to achieve the desired approach toplug flow behavior.

[0045] Referring now to FIG. 1, in a preferred embodiment, at least someportions of reactor 10 are provided with heat transfer means. Heattransfer in the present invention should be simple because the slurryacts as a liquid. Therefore, an internal coil, a vertical multi-tubebundle, or various external heat exchanger designs may (can) be used toeither remove or add heat. A preferred heat exchanger is a verticalmulti-tube bundle such as that shown at 12 a. This bundle type of heatexchanger is optimum because it is inexpensive, does not plug, andprovides a uniform radial temperature profile in the reactor section.Also, it has been found that such bundles have a heat transfercoefficient of >15 BTU/hr-ft2-° F. (78.2 Cal.,kg./hr-m2-° C.), which ishigh enough to control the temperature of most mildly endothermic orexothermic reactions. Conventional techniques for calculating the heattransfer coefficient suggest a much smaller heat transfer coefficient(<3 BTU/hr-ft2-° F.) (14.6 Cal.,kg./hr-m2-° C.) because the tubevelocities are low (laminar flow). The fact that the actual heattransfer is higher suggests that the heat transfer is enhanced by thepresence of the fluidized particles in the reaction medium.

[0046] To practice the process of the present invention, a tube 14 isfilled with catalyst and liquid reactants are pumped in to form a slurrywhich is injected into reactor 10. Pilot reactor 10 includes a means togauge the level of the catalyst slurry. In the pilot reactor 10 shown inFIG. 1, this gauging means may consist of two windows 16 a and 16 b, oneabove the other. After the catalyst slurry is injected from tube 14 intoreactor 10, the level of the slurry is adjusted to the level of topwindow 16 a. Because the slurry expands when the liquid reactants areadded, the slurry is drained, primarily through valve 13 a, until theslurry reached the level of lower window 16 b, which is about 6″ (15.24cm) below window 16 a. The function of lower valve 13 b primarily is toremove large catalyst particles that drift to the bottom of the reactor.The means for gauging the level of the slurry may consist of any knownslurry level sensor or system.

[0047] A slurry is not required for this invention to work. The reactormay be filled with powdered catalyst prior to feeding the liquidhydrocarbon reactant.

[0048] Once reactor 10 substantially is filled with slurry from tube 14,the liquid reactants are fed into reactor 10 via line 18. In pilotreactor 10, the liquid reactants may be fed through a porous metal plateto encourage even distribution of the reactants. In a commercial scalereactor, the use of any conventional liquid distributor means wouldsuffice. The liquid reactants preferably are fed into reactor 10 via aline 30 at a velocity such that the liquid reactants will cause “bedlifting,” or “fluidization” of the largest particles at 50% of themaximum feed rate. The preferred diameter of the reactor can becalculated using known procedures which depend upon the requiredvelocity of the fluid reactants. See, e.g., R. Perry and D. Green,Perry's Chemical Engineering Handbook, McGraw Hill (6th Ed. 1984), p.20-59, incorporated herein by reference. The net effect of the liquidreactants rising through the catalyst should be a dense slurry bed whichhas approximately 50 volume % catalyst and behaves like a liquid.

[0049] The invention may be used in connection with any reaction inwhich the catalyst may be used in a fluidized bed. One nonlimitingexample includes the conversion of 5-vinyl-2-norbornene (“VNB”) to5-ethylidene-2-norbornene (“ENB”).

[0050] With respect to this one embodiment involved in the followingexamples, the conversion of VNB to ENB is exothermic; therefore, thereaction cannot proceed to a high conversion unless the reaction mixtureis cooled at certain intervals. In pilot reactor 10, four non-cooledtube segments 12 b optimally were about 4″ (10.16 cm) diameter, about 6″(15.24 cm) long, and were interrupted by cooled segments 12 a of about18″ (45.72 cm) in length. The optimum tube lengths of 12 a and 12 b willdiffer depending upon how exothermic or endothermic a reaction is;however, one of skill in the art should be able to calculate the optimumtube lengths for any particular reaction using known methods which donot require undue experimentation. The height to diameter ratio of theuncooled reactor zone in this embodiment is 6:1.

[0051] In order to achieve the beneficial “plug flow” characteristic, itis essential to have sufficient bed height of relatively quiescentcatalyst particles with about 50% catalyst as previously described. Thisis not achieved in the heat transfer zone just described. In fact, theheat transfer zones interrupt the plug flow regime of the rector andshould therefore, be minimized.

[0052] Reactor 10 is equipped with an exit line 20 to remove the ENBproduct once the reaction is complete. A filter is placed in line 20 toremove minor amounts of catalyst particles which are still entrained inthe product.

[0053] An example of a commercial scale reactor 10 which is suitable foruse in the present invention is shown in FIG. 2. Reactor 10 shown inFIG. 2 may be provided with a separate mixer 22 in which the catalystslurry is prepared. In the depicted embodiment, a catalyst slurry isformed by mixing the catalyst, which is fed to mixer 22 via line 24,with the liquid product, which is fed to mixer 22 via line 26. Thecatalyst then is injected into reactor 10 via line 28 using a catalystfeed pump 29.

[0054] In a preferred embodiment, reactor 10 substantially is filledwith catalyst slurry, preferably as detected by slurry level sensorsinside reactor 10, before the liquid reactants are added via line 30.Once again, reactor 10 is provided with a heat transfer means 32, andthe length of the zones of the reactor which should or should not havesuch heat transfer means can be determined by the exothermicity orendothermicity of the reaction. Spent catalyst may be removed fromreactor 10 via line 34, and the desired product may be removed fromreactor 10 via line 36.

[0055] Preferably, the reactor is provided with filters 38 through whichthe liquid product passes before it is removed via line 36. Anyconventional solid/liquid separation equipment may be used, includinghydrocyclones, which would retain any catalyst fines remaining in theproduct, and internally and/or externally mounted back-flushablefilters, as illustrated at 37 in FIG. 2. It is also helpful for the topof the reactor, above the fluid catalyst level, to be of a largerdiameter than the fluid bed section. The lower liquid velocities in thislarger diameter section promotes settling of catalyst particles beforethe product liquid is removed.

[0056] One potential problem that might be expected using the presentinvention would be liquid bypassing and/or back-mixing. Liquid bypassingis minimized in the present invention because the reaction mixture actslike a dense fluid. In laboratory testing, residence time distributionswere determined for an 18″ (45.72 cm) long×1″ (2.54 cm) effectivediameter powdered alumina bed. The residence time distributions showthat the liquid acted basically like laminar flow.

EXAMPLES

[0057] The following examples illustrate both prior art methods and thepresent invention. Comparative Example A demonstrates that fluidizationof a powdered catalyst by a liquid without bubbles is achievable over arange of velocities and bed expansion does exist. Example 1 illustratesthe use of this fluidization technique on the high conversion process ofisomerizing VNB to ENB on a laboratory scale. Example 2 illustrates thesame isomerization process that was conducted in Example 2, but was doneon a larger scale to demonstrate operability with heat transferequipment. Comparative Example 4 demonstrates the negative affect ofagitation on the reaction.

Example A—Comparative

[0058] Example A demonstrates that fluidization of a powdered catalystby a liquid without gas bubbles is achievable over a range ofvelocities. An “armored sight glass” which was 0.53″ (1.3462 cm) wide,1.37″ (3.4798 cm) deep, and 18″ (45.72 cm) tall was used as the“reactor.” The “reactor” was equipped with a porous metal distributionplate on the bottom and filled with 86 grams of powdered alumina, whichhad an average particle size of 78 microns.

[0059] A stream of mixed xylenes, at 27°C., was used as the liquidfluidization medium and flowed through the porous metal distributor intothe bottom of the “reactor.” The superficial velocity of the fluid waschanged by adjusting the feed rate of the mixed xylene stream. The bedheight was noted 30 minutes after the velocity was altered. Tests wererun using both increasing and decreasing velocities. The bed expansionratio was calculated by dividing the expanded bed height by the originalbed height. The results of these tests are shown in FIG. 2. Thisdemonstrates that the bed becomes fluidized at a superficial liquidvelocity of less than 0.01 ft/sec (0.3048 cm/sec). Catalyst carryoverout the top of the reactor was insignificant, and the fluid bed behaviorwas still evident at a liquid superficial velocity as high as 0.08ft/sec (2.4384 cm/sec). This illustrates how the bed expands, behaves,and operates.

Example 1—Invention

[0060] Example 1 illustrates the use of this fluidization technique onthe high conversion process of isomerizing vinyl norbornene (VNB) toethylidene norbornene (ENB) on a laboratory scale. An alkali metal solidbase catalyst was prepared, using the powdered alumina from Example A,and as described in U.S. Pat. 3,405,196 (Wolff), which is herebyincorporated by reference for purposes for U.S. practice. The sameequipment used in Example A was used in this Example 1.

[0061] 86 grams of the prepared catalyst were placed in the reactor andthe reaction was carried out at atmospheric conditions.

[0062] The flow rate of the VNB reactant ranged from 2 ml/min to 10ml/min, which corresponds to a superficial velocity range of 0.014ft/min. (0.007112 cm/sec) to 0.070 ft/min. (0.03556 cm/sec). The feedtemperature was 80 degrees F. (______ degrees C.), and the effluenttemperature was 95 degrees F. (______ degrees C.). A conversion of99.8%-99.9% of the equilibrium conversion was achieved. Even though thisparticular chemical reaction is exothermic and the reaction cannotproceed unless the reaction mixture is cooled at certain intervals, theheat losses through the reactor wall to the air were sufficient toremove the heat of reaction on this small scale, such that heatexchanger equipment was not necessary.

[0063] This example illustrates that the fluid bed reactor canapproximate plug flow behavior of the reactant(s) as evidenced by thehigh conversion rates. This would not have been possible in a reactorthat was agitated either mechanically or by the use of gas bubbles, asillustrated in Example 3.

Example 2—Invention

[0064] Example 2 illustrates the same isomerization process that wasconducted in Example 1, but was done on a larger scale to demonstrateoperability with heat transfer equipment. The reactor used in thisexample had the configuration as shown in FIG. 1, consisting of fourreactor sections which were separated by three shell and tube type heatexchangers. The heat exchangers were used during the reaction to removethe heat of reaction. The purpose of this test was to prove that it waspossible to achieve the desired high conversions using the fluid bedconcept in a reactor configuration on a larger scale, using a feed rateof 20 lbs/hr (1514 mls/min) rather than the 2-10 mls/min flowrate, asdemonstrated in Example 1.

[0065] The heat exchangers of the reactor consisted of four tubesmounted inside of a shell, with the tubes having an internal diameter of0.9″ (2.286 cm) and a length of 18″ (45.72 cm). The exchangers wereoperated such that the isomerization reaction was run on the tube sideand the cooling agent, chilled water, was run on the shell side.

[0066] The bottom three reactor sections were comprised of 6″ (15.24 cm)long segments of 4″ (10.16 cm) Schedule 10 stainless steel pipe [4.26″(10.8204 cm) internal diameter] attached to the exchangers and thedistributor with flanges. The reactor sections each had a thermocoupleinserted three inches from the bottom of the respective section, and thebottom section had a port that allowed the withdrawal of spent catalyst.The second and third sections from the bottom had ports that allowed theaddition of air-sensitive catalyst to the reactor. The top reactorsection was 18″ (45.72 cm) long, and had 2 sets of opposing glassviewing ports that allowed the visual monitoring of catalyst level andsurface dynamics.

[0067] VNB was fed to the bottom section of the reactor through a porousmetal plate distributor that covered the bottom of the reactor.

[0068] Catalyst, like that used in Example 1, was added to the reactoruntil the desired conversion was obtained. At steady state condition,3500 grams of catalyst were present. After that point, enough catalystwas added to the reactor to make up for losses due to deactivation bypoisons in the process feed.

[0069] Liquid product was removed from the reactor through a ¼″ (0.635cm) hole in the top flange. VNB was fed at the rate of 20 lbs/hr(544.311 kg/hr) [0.06 ft/min (0.0305 cm/sec) superficial velocity in thereactor sections] of VNB was fed to the bottom of the reactor for 36hours.

[0070] A steady state temperature profile was set up in the reactor,with the reactor sections operating, from the bottom to the top of thereactor, at 112° F. (44.44° C.), 115° F. (46.11° C.), 108° F. (42.22°C.), and 105° F. (40.56° C.). The heat transfer coefficients weremeasured, and were found to be between 15 and 30 BTU's/hr-ft2-° F.(73.2-145 Cal.,kg/hr-cm2-° C.) for the heat exchanger sections.

[0071] After steady state was achieved, the VNB was converted to ENB ata conversion greater than 99.9% of the equilibrium conversion.

Example 3—Comparative

[0072] This example 3 illustrates the effects of having agitation viagas bubbles in the reactor. Example 2 was repeated except that 105 cubiccentimeters of nitrogen gas was injected for less than a 1 minute (60seconds) time period into the catalyst feed part of the bed, whichcorresponds to the residence time of the bed, resulting in the formationof gas bubbles in the reactor bed zone. The disturbance in the bedresulted in a decrease in conversion from 99.8% to 98.5%.

[0073] This example illustrates the importance of minimizing anydisturbance to the quiescent liquid fliudized bed in order to achievethe approach to plug flow behavior necessary for reactions where closeapproach to thermodynamic equilibrium is desired.

We claim:
 1. A continuous process for producing a desired hydrocarbonproduct from a conversion chemical reaction which utilizes a solidcatalyst in powdered form comprising: a) providing a reactor having atop portion and a bottom portion wherein the length to diameter ratio ofthe reactor is greater than about 2:1; b) loading a powderedheterogeneous catalyst into said reactor; c) feeding to said bottomportion of said reactor at least one liquid reactant at a velocitysufficient to disperse said catalyst in said liquid reactant without theuse of agitation or back mixing to form a bed reaction zone wherein saidvelocity is at least equal to the minimum fluidization velocity and lessthan the minimum entrainment velocity wherein catalyst exits said bedreaction zone in the liquid; e) subjecting said liquid reactant tocatalyzing conditions in said bed reaction zone whereby said desiredhydrocarbon product is formed; and f) removing said desired hydrocarbonproduct from said top portion of said reactor.
 2. The process of claim1, wherein said catalyst and said liquid reactant are continuouslyreplenished.
 3. The process of claim 1, wherein the conversion rate ofthe catalytic reaction is higher than 90%.
 4. The process of claim 1,wherein said desired hydrocarbon product is 5-ethylidene-2-norbornene.5. The process of claim 4, wherein said catalyst is an alkali metal onalumina and said at least one reactant is 5-vinyl-2-norbornene.
 6. Theprocess of claim 1, wherein said reactor is equipped with means for heattransfer.
 7. The process of claim 1, further comprising withdrawingspent catalyst from said reactor.
 8. The process of claim 7, whereinsaid spent catalyst is regenerated.
 9. The process of claim 8, whereinsaid regenerated catalyst is fed to said reactor.
 10. The process ofclaim 2, wherein said catalyst is fed to said reactor in the form of aslurry comprising at least two components selected from the groupconsisting of said desired hydrocarbon product, said catalyst, and saidat least one liquid reactant.
 11. The process of claim 1, wherein theconversion rate of the catalytic reaction is higher than 95%.
 12. Theprocess of claim 1, wherein the conversion rate of the catalyticreaction is higher than 97%.
 13. A hydrocarbon product produced by aprocess using a heterogeneous slurry catalyst comprising a) providing areactor having a top portion and a bottom portion; b) feeding to saidreactor a slurry comprising a powdered heterogeneous catalyst; c)subsequently feeding to said bottom portion of said reactor at least oneliquid reactant at a velocity sufficient to disperse said catalyst insaid liquid reactant to form a dense slurry bed reaction zone having atop portion and a bottom portion; d) subjecting said liquid reactant toappropriate catalyzing conditions whereby said desired product isformed; and e) removing said desired product from said top portion ofsaid reactor.
 14. A reactor for producing a desired hydrocarbon productusing a heterogeneous slurry catalyst comprising a) a top portion and abottom portion; b) means for feeding a slurry to said reactor comprisinga powdered heterogeneous catalyst; c) means for subsequently feeding tosaid bottom portion of said reactor at least one liquid reactant at avelocity sufficient to disperse said catalyst in said reactor to form adense slurry bed reaction zone having a top portion and a bottomportion; d) means for subjecting said liquid reactant to appropriatecatalyzing conditions whereby said desired product is formed; and e)means for removing said desired product from said top portion of saidreactor.